[HN Gopher] How do jewellers capture every last particle of gold...
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How do jewellers capture every last particle of gold dust? (2017)
Author : EndXA
Score : 171 points
Date : 2024-07-15 22:48 UTC (1 days ago)
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| JackMorgan wrote:
| Fascinating. Now I wonder why jewelers don't always just work in
| sealed containers with vacuums like what is used for sand
| blasting.
|
| I wonder now how much gold dust gets accumulated in the lungs of
| goldsmiths. I wonder if they take organs to check for sweeps.
| utensil4778 wrote:
| Because the work is remarkably intricate. It requires you to
| get real close and personal with the work, usually with
| magnification. It requires complete and unimpeded dexterity of
| your fingers, so bulky gloves are absolutely not an option.
|
| Depending on the work, it may also require frequent trips to
| the hearth for torch work. You _really_ don 't want to use an
| oxy/propane torch in a sealed glovebox.
|
| In short, it's too much hassle and makes the work more
| difficult and much slower.
| pjd7 wrote:
| They work with sulphuric acid, oxy/acetylene/propane torches.
| Some processes give off cyanide fumes. Ultrasonic baths with
| ammonia based solutions to clean polishing compounds off etc.
|
| You need outside air ventilation.
|
| There is lots of mechanical suction for things like polishing
| to capture the waste material for post processing.
|
| Most will wear a leather apron for heat / burn protection and
| capturing fine dust/dirt from polishing compounds. I suppose
| you could destroy that eventually in a giant smelter.
| nelsondev wrote:
| Sounds like you are ready to open a crematorium that
| specializes in former jewelers.
| foxylad wrote:
| Or anyone with gold teeth.
| nanomonkey wrote:
| More modern jewelry manufacturers are moving towards this.
| There are laser welders with glove boxes and microscopes that
| are auto shielding, also cnc milling machines in completely
| enclosed environments where the lubricants that are sprayed on
| the milling ends are filtered for metal.
|
| I was a jeweler for a couple years and the common practice was
| to have carpet and a sticky trap at the door. The carpet was
| torn up every few years and used to throw a company vacation.
| ortusdux wrote:
| Reminds me of the people that scavenge gold and gems off New York
| sidewalks
|
| https://www.forbes.com/sites/timworstall/2011/06/22/new-york...
|
| https://www.igi.org/digging-for-gold-in-new-yorks-sidewalks/
| ainonsense44 wrote:
| > In March, 2022 video creator Klesh, who sells the paydirt he
| recovers from various areas, ...
|
| Person, who makes money off people believing they can find
| treasure, makes video about how easy it is to find treasure.
| "Oh btw you can buy these utils for 25$ in my store."
|
| Media literacy says : trust level 2/10, most probably lies and
| marketing
| greyface- wrote:
| Here's a series of videos showing the recovery and refining
| process:
|
| https://www.youtube.com/watch?v=ePEwr-VxqXE
|
| https://www.youtube.com/watch?v=WKGhmt7jgMg
| pianoben wrote:
| I love this guy's channel! It's interesting, unpretentious, and
| he has such a _wealth_ of chemical and metallurgical knowledge.
| The reactions and processes he shows are amazing.
| sumtechguy wrote:
| I watch this channel a lot. He has a few where he is refining
| electronic waste. He usually says that is not really worth it
| due to the time it takes him to do it and small amounts he gets
| and can get easily lost in the different stages of extraction.
| Most of the stuff he does is estate sales and melting down
| that.
| nielsbot wrote:
| Interesting term of the trade in the article: "lemel". (Metal
| filings)
|
| Wiktionary: From Middle English lymail, from Anglo-Norman
| limaille, from Latin limare, a form of limo ("to file"); see
| further there.
| pjd7 wrote:
| I did my jewellery trade in Australia (hence the correct spelling
| for me). We used to keep all our emery paper, old polishing
| wheels etc and send them off ever few years to be burnt &
| refined.
|
| When the building we were in got renovated some enterprising guys
| in another workshop ripped up their floor boards and their
| neighbouring empty suites and got all the precious metals out of
| the gaps between the floorboards.
|
| The building was 11 stories and was predominantly filled with
| small jewellery workshops with 2-5 people per business. And a lot
| of adjacent businesses (trade supplies, stone merchants etc).
| doctor_eval wrote:
| Curious where that was? My partner was a jeweller in the
| Nicholas Building in Melbs.
| pjd7 wrote:
| 250 Pitt St Sydney around 2002-2003.
| candeira wrote:
| A friend of mine had an art studio at the Nicholas Building,
| and I got to speak with a jeweller who told me that he still
| did a lot of bespoke work in wedding rings, especially for
| tradies who would otherwise wear down store-bought rings
| because they were solid gold and therefore softer. I don't
| remember the details, but he specialised in harder alloys
| that are nevertheless mostly gold, and therefore "good as
| gold" for a wedding ring.
|
| Would that be your partner?
| doctor_eval wrote:
| Not my partner, but I bet they knew each other, it was a
| great little community and she was there for the better
| part of 20 years.
|
| Great parties in the 00's!
| ironmagma wrote:
| But do you pronounce it "jew-el-ry" or "jull-uh-ry"?
| janderson215 wrote:
| Probably jew-el-ery
| dorkwood wrote:
| In Australia, it's neither. It's jool-ry.
| euroderf wrote:
| Also in western NY state.
| loudmax wrote:
| Wandering off topic here, but fans of Mad Max 2 (The Road
| Warrior) may remember Emil Minty as The Feral Kid. He only had
| a few other roles as a child actor, then went on to become a
| professional jeweler. According to one podcast, he was already
| fashioning necklaces out of the tabs from discarded cans on
| set. In the end, a far healthier career choice than many other
| child actors of the same era.
| pregseahorses wrote:
| Saw it in Karachi last year: a street containing exclusively gold
| workshops was blocked for traffic Sunday morning, guarded
| officially by the police, while the staff hired by the co-op
| swept every inch. Apparently this is a weekly routine.
| notJim wrote:
| Reminds me of the stories of people in NYC's diamond district
| making their living by looking for dropped gemstones and tiny
| bits of gold.
|
| https://nypost.com/2011/06/20/got-his-mined-in-the-gutter/
|
| https://www.youtube.com/watch?v=TfrqUNFtM6A
| kjkjadksj wrote:
| I'm wondering how these gemstones even make their way on the
| street. Are jewelry workshops really so messy and flippant
| with this product that it presumably gets caught up on people
| and just falls off their clothes when they leave from work?
| Is it from crappy stone settings falling off immediately on
| leaving the stores? Seems so strange to me how such a
| valuable product ends up dispersed in the environment like
| this.
| mtnGoat wrote:
| Some jewelers are dealing with things of great enough value
| that some gold dust or small stones doesn't matter. Most
| jewelry value is not in the gold or gems, it's in the eye
| of the beholder so to speak. So losing the actual ring is a
| much bigger loss than the gold/gem value. However, a guy on
| the street that isn't dealing in six figure goods, places
| great value in that small gold amount.
|
| Most people would be amazed at how little, when not in a
| shop under bright lights, jewelry is actually worth. Let's
| just say they aren't selling gold, they are selling
| emotions and hype. And many customers get extremely angry
| when they go to resell and find out how little it's worth.
| You'll be lucky to get a tenth of what you paid for the
| stones.
|
| Source; my wife ran the biggest gold buying store in
| northern LA county for a few years.
| eru wrote:
| Yes, but any savings go straight to the bottom line.
| goldinquiry1 wrote:
| Right - if spot price per oz is $2,418.95 and say
| hypothetically I am sourcing it for $1700/oz there seems
| to be a reasonable amount of margin there if you can find
| a buyer for it.
| fbdab103 wrote:
| It is a global market, why in the day of the internet,
| would someone cut you a 30% margin? There might be some
| hassle crossing international borders, but gold is not
| generally illegal where there is an outsized risk in
| moving it.
| mtnGoat wrote:
| The margins mentioned are about in line with most "gold
| buyers" that have store fronts. 70% of spot is a decent
| starting point for "salvage" gold.
|
| If it's in any form but rounds or bars, it'll need to be
| melted down which has a cost. So it can be made into a
| form that can be resold closer to spot value.
|
| The margin are actually even better if you melt them
| down. it's really hard to buy physical gold at spot,
| single ounces/grams go for a few points higher.
| owenmarshall wrote:
| Anyone offering a discount of over 2500 basis points to
| participate in what might be one of the most accessible
| markets across the world isn't offering actual value,
| they've just found a good mark.
| bruce511 wrote:
| I second this, jewelry has very little value on the 2nd
| hand market.
|
| Gold, Silver etc have a daily published value, and you
| can expect a number close to that (allowing for margin).
| But "precious stones" are really not all that precious,
| or rare.
|
| When selling (to a dealer) you discover the margins they
| make- often upwards of 90% (as my father discovered
| selling jewelry he inherited.) To be fair, crafting takes
| significant labor and most old jewelry has to be melted
| down and recrafted.
|
| None of this negates the significance of one person
| giving another jewelry. That adds substantial sentimental
| value which is what makes them valuable at all.
|
| (It does make me smile though when movies use uncut
| diamonds as some sort of compact currency...)
| fbdab103 wrote:
| So, resale market on stones is trash. What is to stop an
| intrepid jeweler from purchasing grandma's/ex-
| spouse's/whatever's precious jewelry for 10 cents on the
| dollar, and reselling it back into circulation as "new"?
| Maybe with a perfunctory shaving off a face to make a
| "new" item. Or is this already regularly done (as I would
| assume)?
| jachee wrote:
| Assay marks.
| mtnGoat wrote:
| Yes that is regularly done. The jewelry buyers take them
| out and sell them in lots for very low cost to just about
| anyone willing to pay, those buyers then recycle the
| stones into settings or back into stores. The buyers are
| buying on pure wholesale value, whereas the end jeweler
| is selling for sentimental value.
| bruce511 wrote:
| That's exactly the point. It's what they do do. If you
| take 2nd hand jewelry to a jeweler you get about 10 cents
| on the dollar.
|
| Some gets resold as is (there's a (limited) market for
| vintage jewelry) but most is reworked. And of course that
| reworking takes significant time and skill.
| xeonmc wrote:
| Yes. I can't recommend enough the manga "Nanatsuya
| Shinobu's Jewelry Box"
| schlauerfox wrote:
| Fashion. I had my great grandmothers rings appraised for
| probate and got the "these are nice heirlooms, utterly
| worthless for resale though, the stones are just an okay
| clarity and the cut is very out of fashion these days.
| Keep them as nice rememberances." They must have said the
| same thing thousands of times.
| teddyh wrote:
| Relevant link: _Have You Ever Tried To Sell A Diamond?_
| (1982) <https://www.theatlantic.com/past/docs/issues/82f
| eb/8202diamo...>
| goldinquiry1 wrote:
| I just posted an Ask HN. Would love to learn more about
| gold selling, in general, as I have a contact that is
| capable of sourcing me gold from Burkina Faso.
| coffeebeqn wrote:
| Sounds like a great way to get scammed! Gold is already
| very liquid with a real time price on multiple metal
| exchanges across the globe.
| mtnGoat wrote:
| Unless you have a lot, you probably won't get close to
| spot price. You might be able to find some local artisans
| that will pay better for small amounts then the big
| houses will. Gold in stamped form has the greatest value.
| Nuggets or mined gold, some buyers are afraid of and
| won't pay until it's melted.
|
| Gold teeth are worth the absolute least.
| ethagnawl wrote:
| > Gold teeth are worth the absolute least.
|
| That was an unexpected kicker. I suspect you or your
| spouse must have a good story about shady people trying
| to work that angle.
| testfoobar wrote:
| How did she confirm that items she was buying contained
| the gold claimed?
| mtnGoat wrote:
| Testing tools, and a lot of knowledge. Knowing what it is
| and where it's made informs a lot. Once in a while you'll
| get someone that is scamming and had stuff made with
| extra thick plating. Most pieces they will cut in half,
| grind a bit off, drill into it, etc. to do an acid test
| to determine gold content, then weigh it.
|
| After a while she just kind of knew what to look out for.
| How people presented the goods, how they acted, etc.
|
| The most shocking part to me, was how many 80s-90s celebs
| would bring in gold to sell. I guess times get rough.
| BobAliceInATree wrote:
| Rubies for watches are synthetic and super cheap.
|
| And the small diamonds are still pretty cheap. He said
| about $100 per carat of small diamonds. It's not surprising
| that they're more casual with this inventory.
| cyberax wrote:
| > Are jewelry workshops really so messy and flippant with
| this product that it presumably gets caught up on people
| and just falls off their clothes when they leave from work?
|
| Boots, not clothes. Diamonds are so sharp that they easily
| get lodged in rubber soles. And then fall out when you
| walk.
| michaelt wrote:
| Grocery store cashiers and bank clerks often don't get to
| leave until they've accounted for every cent that should
| be in their till.
|
| One would think diamond merchants would take the time to
| be equally careful, if not moreso.
| BobAliceInATree wrote:
| Most of these businesses in the district are tiny,
| family-owned businesses, so there's a huge amount of
| implicit trust there.
|
| But also, these tiny stones really aren't worth much.
| What you're asking is like Home Depot making sure to
| account for every single nut & bolt so none are stolen or
| lost. It would cost far more in time & labor then what
| you'd get back in return.
| gowld wrote:
| It's not such a valuable product. It only supports one low-
| paying full-time job, and who knows how long before the
| streets have been cleaned out of past accumulation.
|
| > Over six days, he says, he collected enough gold for two
| sales totaling $819 on 47th Street.
| jaggederest wrote:
| There's a Cody's Lab video where they refine highway dust for
| platinum group metals leaking from catalytic converters:
|
| https://www.youtube.com/watch?v=v5GPWJPLcHg
| ainonsense44 wrote:
| That video is a guy selling a dream, to sell his own products
| to the viewer, who believe in the legitimacy of the findings
| shown in the video.
|
| I call marketing stunt. Most unlikely not a truthful
| representation of what to expect when doing it yourself.
| blackbaze wrote:
| Ingenious! Why not. Beats getting it out of the ground. Possibly
| good for the environment as for a given gold demand less needs to
| be mined.
| CrispyKerosene wrote:
| This is why if you ever get jewellery repaired or resized, ask
| for the scrap to be returned.
|
| Some less than reputable places will try to off-handedly say it
| was discarded. They don't lose anything.
| kjkjadksj wrote:
| Seems like this is only netting you $8 or so.
|
| https://old.reddit.com/r/jewelry/comments/vno1to/question_re...
| xcv123 wrote:
| That sounds miserable and desperate. A couple of dollars worth
| of scrap shavings. What will you do with that? Just let them
| have it.
| mtnGoat wrote:
| Yea it's like people that bring in their dead ancestors
| teeth, no one wants to buy an old tooth and certainly not one
| with $5 worth of gold in it.
| joelfried wrote:
| I'll pay you $5 for gold teeth and make a tidy profit. This
| article from 2019[1] said $40-92 per crown. Multiply by 1.6
| based on the way gold has appreciated since 2019[2] and
| that's $65-147 or so per tooth.
|
| [1] https://thegoldcenter.com/how-much-gold-is-in-a-dental-
| crown... [2] https://www.macrotrends.net/1333/historical-
| gold-prices-100-...
| xcv123 wrote:
| LOL. Imagine being so miserable and desperate that you
| rob your grandmothers grave for a few dollars.
| mtnGoat wrote:
| More and more graveyards are being fenced off and secured
| for this reason sadly. Plus generations ago some opted to
| be buried with their wedding rings and such. I know some
| smaller family ones in my area of central Washington have
| been robbed.
| mtnGoat wrote:
| But you also have the cost of man hours, marketing that
| you buy gold, finding a smelter that will take teeth, or
| do it yourself. That's not all profit, plus you don't
| know the gold weight until you remove it from the tooth.
| Which is risk. Plus it's possibly a biohazard.
|
| These people buy millions per day in gold, I'm sure if it
| was profitable they wouldn't turn it away.
|
| You can try it though, go to all the gold stores in your
| area and tell them you'll buy all the teeth they bring
| in.
| COGlory wrote:
| My father (makes fake teeth) rips up his carpet every decade and
| has it burned and the metal dust in it melted down. Usually gets
| $10k-$15k.
| 7thpower wrote:
| I would just get a Roomba, bling it out, and then destroy it
| when it ripped one of my charger cables out of the wall.
|
| Or just get sheet vinyl or something.
| eru wrote:
| A carpet is probably better at holding on to particles as
| people walk over it.
|
| A vinyl sheet will just lose it to people's boots.
|
| 10k$ over ten years is also not that much per day. So he
| might be happy to make the trade-off for having a nice
| carpet.
| 7thpower wrote:
| That's fair. I was just surprised to hear he'd be using
| carpet in the first place. I'm sure he knows what he's
| doing, not questioning him.
| PhasmaFelis wrote:
| Carpet is probably the best thing for it, since the dust
| will work its way down in and stay there instead of
| sticking to your shoes and winding up all over the city.
| thaumasiotes wrote:
| > 10k$ over ten years is also not that much per day.
|
| It would be about $2.75 per day, an insignificant amount,
| but it's much worse than that because you earn it all at
| once at the end of the ten-year period. So you're making
| (almost) $2.75 a day toward the end of the period, and a
| lot less than that toward the beginning.
| southernplaces7 wrote:
| Really though, it's more a sort of diligence bonus on top
| of the regular earnings he makes from his teeth
| manufacturing business. Looked at that way, it's pretty
| impressive quickly obtain an otherwise lost 10-15K per
| decade as opposed to just losing money on carpet removal
| once a decade. And all of it for, what? a few hours of
| work?
| COGlory wrote:
| Yeah, it's partly a tradeoff for convenience. The carpet
| helps capture dust which makes everything more breathable
| in the lab as well. I'm sure bigger labs have more
| sophisticated facilities, but he's just one guy in his
| attic.
| 00N8 wrote:
| Reminds me of my favorite story from the Manhattan project: The
| project needed massive amounts of wire for all the equipment, but
| copper was in short supply for the war effort. They ended up
| working out a deal with the Treasury Department to use silver
| instead, since it was an even better conductor & apparently more
| available at the time. Part of the deal involved making sure not
| to lose any silver & IIRC they managed to not only return all the
| borrowed silver, they even found some extra to return by tearing
| up the floors in all the mints, warehouses & workshops, to
| incinerate & reclaim the precious metal, just like in the
| article!
| dredmorbius wrote:
| Do you have a source on that?
|
| I'm finding "The Manhattan Project: the Important Role Silver
| Played In the Building of the Atomic Bomb"
| <https://discover.hubpages.com/education/The-Manhattan-
| Projec...> (2015).
| 00N8 wrote:
| I think I first heard about it in a Scott Manley video -
| maybe this one, https://m.youtube.com/watch?v=JNT28WKAxgs - &
| read more on Wikipedia & possibly elsewhere
| glompers wrote:
| Here's a more official source:
| https://www.osti.gov/opennet/manhattan-project-
| history/Event...
|
| Groves' deputy, Nichols, who was responsible for the loan,
| also told the story in more detail in 1987 memoir, "The Road
| to Trinity."
| glompers wrote:
| Directly related to recapture of gold -- and related to the
| Manhattan Project by Farm Hall [0] too -- is the tale of
| German objector Max von Laue's Nobel Prize medal, which was
| dissolved during WWII and recast out of solution afterward
| [1]
|
| [0] https://en.m.wikipedia.org/wiki/Max_von_Laue#Post-war
|
| [1] https://en.m.wikipedia.org/wiki/Max_von_Laue#Hidden_Nob
| el_pr...
| jaggederest wrote:
| Another fun Manhattan fact: They needed a code name for
| plutonium, so they called it "copper", but what was a poor
| scientist or engineer who needed to use actual copper to do?
| The official code name for copper was "Honest-to-God copper".
| thinkfaster wrote:
| And they wondered how the Soviets infiltrated the project so
| thoroughly.
| drunkonvinyl wrote:
| Nothing like H2GCu. It's even just pennies on the dollar.
| fbdab103 wrote:
| I am intrigued at how much thought went into "copper". Was
| the thinking that everyone's eyes would glaze over at such a
| common material? My initial reaction would be to use a
| different rare element. However, a rare element might draw
| more scrutiny to the casual observer. Then again, the
| potential for confusion is incredibly high. Interesting
| spycraft.
|
| Supposedly the opsec at the Manhattan Project was so good,
| significant portions of the workforce had no idea on what
| they were laboring. Post war interviews thought the facility
| was all a sham, dedicated to nothing but medical testing.
| TylerE wrote:
| Copper had the advantage of already being directed 100% at
| the war effort.
| bell-cot wrote:
| And almost all of that for bulk uses like shell casings
| and electrical wiring - vast supply chains which no
| competent enemy agent would waste time looking into.
| lostlogin wrote:
| > vast supply chains which no competent enemy agent would
| waste time looking into.
|
| Isn't this exactly what should be looked into? Find weak
| point and hit them. Germanys ball bearing plants and oil
| refineries got targeted this way.
| bell-cot wrote:
| If the Axis had been dropping 1000+ tons of bombs on
| American industry every day, then _maybe_ that would have
| been rational.
|
| Similar if the Axis had large-scale resistance forces
| operating in America, able to sustain at-scale acts of
| industrial sabotage.
|
| But the Axis already knew that America had a huge copper
| industry. With no way to affect that industry, at scale -
| long lists of American copper mines, refining facilities,
| factories, etc. were no more valuable to the Axis than
| collections of apple pie recipes.
| zeckalpha wrote:
| You're thinking of the honest-to-god copper supply chain,
| not the "copper" supply chain.
| rtkwe wrote:
| There wasn't much of a Nazi spy presence in the US much
| less effective saboteur operations. One of the few people
| convicted for espionage had their conviction overturned
| because the information they passed was publicly
| available. The US was never under much direct threat,
| there were a smattering of attacks and raids on the West
| Coast but those didn't amount to much. Extreme distance
| was a better shield than any secrecy or military might,
| it's part of why the post war years were so good and
| continued for decades afterwards, the US was completely
| untouched and the rest of the (then) modern world was
| bombed to absolute smithereens.
|
| https://www.neh.gov/article/nazi-spies-america
| to11mtm wrote:
| The bearing plants didn't have much of a long term impact
| if I recall...
|
| The oil campaign OTOH, worked out well.
|
| I'd guess actually going after stuff like wire/brass
| casing production, while it could have an impact, the
| 'ROI' is likely lower than more important logistics meta-
| targets (i.e. oil and gas production and transport
| infra/equip) and those are far easier to 're-boot-strap',
| one can theoretically draw copper wire from their garage
| with a reasonable base starting piece and draw jig/rig.
|
| Also, like bearings, it's easier to 'surplus'. Surplus
| Oil sitting in a field or penetrable location? Obvious
| easy pickings. Stockpiled wire? I mean you could but
| frankly even if you burned/melted all the wires someone
| can just collect it and re-make wire. It's not like oil
| where the resource gets completely destroyed in the
| process.
|
| (Ammo depots, OTOH, would make sense.)
| SnorkelTan wrote:
| My dad's relative (uncle I think?) ran the team that
| fabricated the detonators for the bombs. They weren't told
| what the purpose was when they built them. They found out
| what the purpose was when they were used.
| to11mtm wrote:
| > My initial reaction would be to use a different rare
| element. However, a rare element might draw more scrutiny
| to the casual observer. Then again, the potential for
| confusion is incredibly high. Interesting spycraft
|
| Worth noting (unless someone else already did) that the UK
| program that technically started before the Manhattan
| Project was called 'Tube Alloys'.
| JoshTriplett wrote:
| That sounds like the start of a story that ends up with wires
| made out of plutonium.
| retrac wrote:
| There is a story to go with that story. The colonel responsible
| for the negotiations with the Treasury would later recall:
|
| > He explained the procedure for transferring the silver and
| asked, "How much do you need?" I replied, "6000 tons."
|
| > "How many troy ounces is that?" he asked. In fact, I did not
| know how to convert troy ounces to tons, and neither did he. A
| little impatient, I responded, "I don't know how many troy
| ounces we need, but I know I need 6000 tons - that is a
| definite quantity. What difference does it matter how we
| express the quantity?"
|
| > He replied rather indignantly, "Young man, you may think of
| silver in tons, but the Treasury will always think of silver in
| troy ounces."
| umanwizard wrote:
| If anyone else was curious like me, 6000 US tons is 175
| million troy ounces.
| mminer237 wrote:
| And worth $5.4 billion dollars at today's prices.
| michaelmcdonald wrote:
| For those wondering like me:
|
| 6000 metric tons of silver is approximately 192,904,200 troy
| ounces, and 6000 US tons of silver is approximately
| 175,000,000 troy ounces.
| mads wrote:
| There is a US ton? My God...
| lobsterthief wrote:
| Yes, many of us Americans wish we would adopt the metric
| system.
| dghughes wrote:
| You did. All your (USA) units use metric then are
| converted to US measurements. The US inch is officially
| 25.4mm exactly.
|
| https://www.nist.gov/pml/owm/si-units-length
| ddingus wrote:
| Yup. And more things are SI units every day.
|
| I use them most of time now. We are getting there slowly.
| dghf wrote:
| And an imperial ton, which is different again.
| hansvm wrote:
| To be perfectly fair, it was a little strange for the
| metric system to have a "ton" unit in the first place.
| Much like a foot or a cup, it's one of those units the
| metric system is trying to replace, but rather than use
| megagrams or something else perfectly sensible within the
| system they already created, they added to the confusion
| by defining yet another "ton" close enough to the
| historical units of the same name.
| hwillis wrote:
| it's because "megagram" and "milligram" are a hassle.
| With the added bonus of mm/MM being used to abbreviate
| millions, I'm personally very grateful for tonnes.
| stonemetal12 wrote:
| The SI unit of measure is the Kilogram, not the gram.
| Therefore they ought to be using the kilokilogram KKg,
| not the Mg.
| immibis wrote:
| Just because the definition is based on 1000 of the base
| unit doesn't mean the prefixes start being weird.
| rad_gruchalski wrote:
| the SI unit for kilogram is kg and not Kg
| wtfmcgrill wrote:
| There's the metric tonne 1000kg, the US short ton 2000lbs
| and the US long ton 2240lbs(1016kg) also known as
| imperial ton. I started calling the metric tonne a
| megagram because I got tired of trying to figure out if
| it was short, long or metric I was dealing with
| boringg wrote:
| The bane of all engineers having to do unit conversions
| and asking clarifying questions around what type of
| ton/tonne.
| RichardCA wrote:
| This is from a web site that's been around since the Web
| 1.0 era: https://www.ibiblio.org/units/dictT.html#ton
| Gupie wrote:
| $30.59 per ounce (current)
| itishappy wrote:
| My colleague told me a story just last week about his father's
| old job at Kodak working in silver reclamation. Same story as
| this article, they chuck _everything_ into the furnace. They go
| so far as to filter the wastewater from employee showers.
| whycome wrote:
| https://www.reuters.com/article/world/india/gold-from-the-gu...
| WalterBright wrote:
| Use a magnet!
|
| Edit: oops, never mind
| eru wrote:
| Magnets only really work for iron.
| askvictor wrote:
| It's a little more complicated than that - gold is a little bit
| magnetic, and heat or light can increase this magnetism
| bayouborne wrote:
| So does that mean it's possible to develop a magnetic
| 'figure-print' for gold?
| cancerhacker wrote:
| In the north east, in spring, we'd use magnets to collect iron
| filings in the street from the snow plows. It was just a thing
| we'd do, no financial interest. We'd keep our haul in 35mm film
| canisters (as was the style at the time!)
| interroboink wrote:
| Reminds me a little of the man who "mines" gold and precious gems
| from the sidewalks in NYC: https://nypost.com/2011/06/20/got-his-
| mined-in-the-gutter/
| hilbert42 wrote:
| I wonder how much precious metal such as gold and semiprecious
| metal such as gallium and indium essentially disappears forever
| in the thousands of tons of electronic waste every year. Does
| anyone know the percentages recovered/lost?
|
| Right, some recovery does occur--gold from edge/contact
| connectors etc. but I'd venture it's only a small fraction of
| what is used annually. And what about LEDs and transistors? I
| wonder if anyone ever bothers to recover the gallium and indium
| from them or whether the amount used isn't worth the effort.
| ars wrote:
| It mostly ends up in landfill. At some point we may be resource
| poor, and but energy rich and we'll use Plasma mass separation
| to separate each element out and reuse the valuable ones. Until
| then it's safely stored there.
| hilbert42 wrote:
| No doubt most valuable elements do end up in landfill and
| most will ultimately be recovered, but we still need to have
| a good handle of what's actually lost or doesn't make it
| there, and or how much leaches out before recovery. (Here we
| don't seem to have decent figures, if anyone knows of any
| authoritative references please post them.)
|
| Hopefully, as you suggest, we will eventually be energy rich
| and can afford mass separation techniques to recover these
| elements. Nevertheless, unless some very cleaver as yet
| uninvented techniques are used then the amount of energy
| involved would likely be enormous (but I'm almost certain
| such techniques will be available in the foreseeable future).
|
| Incidentally, for the same reason, I'm not overly worried
| about the necessity for having inordinately long-term storage
| for nuclear waste (hundreds of thousands of years), as in an
| energy-rich world there'd be enough energy to enable the use
| of transmutation techniques (along with fast breeders, etc.)
| to ensure these dangerous byproducts are 'burnt' to harmless
| materials. Basically, whilst nuclear waste is a big problem
| it's a comparatively short-term one.
|
| That said, we're doing a pretty poor job of repurifying
| recycled materials now and the reasons are multifold. I'll
| give an example I've come across but there are hundreds more.
| Batteries of any kind should never be thrown away because of
| the valuable materials they contain. To my knowledge, with
| the exception of lead-acid batteries, an unknown amount of
| used battery material is recycled annually, but the
| effectiveness of what is actually recycled is limited due (it
| seems+) to the difficulty of repurifying said materials.
|
| For example, recycled reagents and other components,
| depolarizers such as manganese dioxide, are (often?)
| insufficiently pure to ensure a battery's long-term storage
| life. Instead of say an alkaline cell having a nominal
| storage life of about six years, impure components contain
| unwanted ionic/conductive materials that lead to a much
| increased self-discharge rate that shortens shelf life (I've
| seen such cells become discharged in only about one third the
| time of those with well-purified materials).
|
| No doubt higher levels of purification would be achieved if
| more energy were inputted into re-refining these materials.
| That said, this re-refining problem isn't just limited to
| batteries but is intrinsic to many recycling processes.
| Probably the best known and most problematic is that of
| separating used plastics together with their
| cracking/depolymerization. Again, it's almost certain these
| problems would be eliminated if enough cheap energy were
| available.
|
| __
|
| _+ Obviously, repurifying recycled materials is different to
| their original refining from ores etc. as repurifying
| processes would be required to remove unwanted materials that
| were never present in the original refining process. I am
| unclear about what this involves and or the extent of its
| deployment as there seems precious little information about
| it in the public domain._
| foota wrote:
| There's discussion about mining landfills to recover these
| kinds of materials. When you rememeber we had to dig it all out
| of the ground, taking it from a dump seems pretty convenient!
| hilbert42 wrote:
| Right, see my reply to _ars._
| dehrmann wrote:
| Depending on the age of the landfill, you can find refined
| aluminum or iron at higher rates than are in ore.
| foota wrote:
| I'm amused by the idea of the vintage of a landfill :-)
| gnicholas wrote:
| > _Hockley Mint has also upgraded its windows so that blinds are
| now encased between panes of glass -- their fabric panels were a
| magnet for precious metal dust -- and it also has an on-site
| laundry to process workers' clothes._
|
| Hilarious -- I guess big tech companies weren't the first to
| offer employees on-site laundry after all!
| GarnetFloride wrote:
| Hospitals used to have on-site laundry, for community
| sanitation and hygiene reasons. of course that was done away
| with for profit reasons.
| sundvor wrote:
| Wow, it sounds like the fine particles are going everywhere in
| the shops.
|
| This made me wonder what the health benefits of having lungs of
| gold might be.
|
| Remains to be seen, perhaps?
| schlauerfox wrote:
| Generally Gold (aurium) is not bioreactive, it's hardly
| reactive at all hence it's lustre in the wild since it doesn't
| tarnish or bond easily. Goldschlager has gold flake in it for
| human consumption. It's generally considered safe to consume
| for this reason. The quantity to make an LD50 of inhaled gold
| would be considerable I imagine, but have no data.
| simonjgreen wrote:
| Piece of advice I've given people having jewellery resized for
| years, is if you are having something resized down then the
| jeweller should be paying you. A surprising number of people
| forget the majority of most jewellery value is the raw material.
| rhplus wrote:
| _A surprising number of people forget the majority of most
| jewellery value is the raw material._
|
| Scrap value, yes, purchase price, no :)
|
| The quick sanity test is to ask why big name jewelers can sell
| the same style ring at all sizes for the same price, despite
| perhaps 25% difference in mass. The majority of the retail
| sales price is not the precious metal value.
| thenickdude wrote:
| Reminds me of Cody's Lab refining platinum from roadside dust
| from the highway: (due to catalytic converters)
|
| https://www.youtube.com/watch?v=v5GPWJPLcHg
| EE84M3i wrote:
| How do the taxes work for this?
| ajb wrote:
| Wonder if that is the last industrial processing still done in
| central London? If you don't count university labs.
| fest wrote:
| I found it interesting that CNC machines aimed at precious metal
| processing have an optional access control system for swarf/dust
| collection bins- presumably so that the technicians operating the
| machine don't steal the "waste" material.
| DonHopkins wrote:
| So prepare yourself for the bloody mayhem and unholy carnage of
| Joshua Logan's "Paint Your Wagon"!
|
| https://www.youtube.com/watch?v=VM5-xFenaZI
|
| https://en.wikipedia.org/wiki/Paint_Your_Wagon_(film)
|
| https://archive.org/details/paint-your-wagon-western-comedy-...
|
| (Money shot at 1:44:30!)
| surfingdino wrote:
| Baird & Co. do the same: ""At the end of the year all of the
| filters are collected together and burned," Baird says.
| "Everything is 'deep cleaned' and burned, all of the filters and
| all of the doormats both inside the refinery and throughout the
| office." Last year the company retrieved PS15,000 worth of gold
| from the deep clean."
|
| https://www.theguardian.com/business/2017/dec/26/the-pots-of...
| mk_stjames wrote:
| > Mr Wibberley recalls when a parquet floor in its own factory
| was ripped up and the precious metals embedded in the wood made
| it worth PS20 per sq m.
|
| I find this interesting, as nicely re-claimed wood flooring
| itself can actually fetch about that price per sq meter these
| days.
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